Dry cleaning establishments utilize various non-aqueous solvents such as perchlorethylene to clean clothes. When cleaning clothes, the dry cleaning solvent may remove fatty acids, soils, dyes, ets., and in order that the relatively expensive solvent may be reutilized it is necessary that these contaminants be effectively removed from the solvent. In recent years, a process is being used in a growing number of drycleaning establishments wherein the solvent is continually passed through filtering tanks containing filter cartridges capable of removing the solvent contaminants. This process is essentially described in U.S. Pat. No. 3,733,267 issued May 15, 1973 to Haase, the disclosure of which patent is herein incorporated and made a part hereof by reference thereto.
The vast majority of dry cleaning filter systems in use today comprise a plurality of vertically-stacked, horizontally disposed, elongated, generally-cylindrical filtering tanks, each tank containing therewithin a plurality of cylindrical filter cartridges placed in end to end abutment within each of the tanks. An annular felt sealing disc is placed between adjacent cartridge end faces to prevent fluid from bypassing the filters. Contaminated drycleaning solvent is pumped into a tank at a peripheral location so that the fluid enters the tank into an annular chamber defined by the exterior of the filter cartridges and the interior of the tank. An exit passageway conducts the fluid from the tank at a central position on a tank end cap so that exiting fluid is withdrawn from the tank through a longitudinally central bore constituted by the central bores of the filters placed end to end. Therefore, the fluid is caused to flow radially through the filters from the exterior thereof to the interior longitudinal bore of each filter.
As shown in the above-mentioned Haase patent, each filter cartridge comprises an annular, generally-cylindrical, sorbant mass usually including attapulgite clay particles mixed with particles of carbon. The sorbant mass is contained between two coaxial perforated sheet metal cylinders enclosed by metal end caps. Placed around the exterior of the outer perforated cylinder is a pleated filtering paper. Pursuant to the above description, drycleaning fluid is caused to first flow through the pleated filtering paper to remove the particulate fibrous contaminants in the solvent and then the fluid passes through the sorbant mass, which is able to remove fatty acids, water soluble soils, water insoluble soils, dyes, and excess water, and which provides deoderization of the solvent, all as disclosed in the Haase patent.
Typically, each of the filter cartridges is approximately one and a half feet long and one foot in diameter. After prolonged use, the paper filter becomes clogged and caked with particulate and fibrous matter and the absorbing qualities of the sorbant mass deteriorate. It is at this time, when the filter cartridge is spent, that the drycleaning establishment operator must remove the filter cartridges from the filter tanks and replace them with fresh ones. Due to the size of each filter cartridge, a single cartridge, when soaked with drycleaning solvent and laden with caked-on particulate and fibrous material, may weigh in the order of 90 pounds.
In order to lessen the burden of the individual removing spent filter cartridges from the drycleaning filtering tanks, filter cartridges have been produced which are half as long as the more conventionally-sized filter cartridges. However, this modification has not proved entirely satisfactory due to the facts that each half-size cartridge requires nearly the same labor costs to produce, two half-size cartridges do not produce the same effective filtering area as one conventional cartridge due to the increased number of sealed end face cap abutments of the half-sized cartridges, and the half-sized cartridges require twice as many metal end face caps as conventionally-sized filter cartridges, and twice as many felt seals for any given filtering tank length, thus increasing production and set-up costs.
According to the present invention, a dry cleaning filter cartridge is produced which is of conventional length and diameter, but which includes an outer cylindrical member which carries the outer pleated paper filter and a separate inner cylindrical member which carries the sorbant mass. Initially, the two members are held in concentric, axial allignment by inexpensive cardboard end cap seal rings adhesively bonded to at least one of the members; however, during use the dry cleaning solvent reacts with the adhesive to disengage the caps from the members and thus allow the separation of the members.
When spent, the entire filter cartridge, soaked with drycleaning solvent and laden with particulate and fibrous matter, may weigh in the order of 90 pounds; however, the inner member carrying the sorbant mass may, in a facile manner, be separated from and slid axially outwardly from the outer member, and thus be removed from the filter tanks separately from the outer member. Thereafter, the outer member may also be pulled from the filter tank separately. The inner member when removed from the filtering tank may weigh 50 pounds, while the outer member may weigh 40 pounds. Thus the total weight of the filter cartridge may be removed in two separate relatively easy operations.
Further, it has been found in use that the cardboard end cap seal rings act as excellent seals between abutting filter cartridges to prevent fluid from flowing between the end faces of adjacent filter cartridges and thereby bypassing the filters. The provision of the initially integral end cap seal rings allows the drycleaning operator to dispense with the conventional felt sealing rings utilized heretofore.
It is therefore the main object of the invention to provide a filter cartridge of the character described, including an annular, generally-cylindrical, outer member carrying a paper filter, and an annular, generally-cylindrical, inner member carrying a sorbant mass therewithin, and being coaxially disposed within the outer member; the inner member being removable from the outer member after the filter cartridge is spent to thereby allow the drycleaning establishment operator to remove two separate, relatively light members from the filtering tank instead of a single, relatively heavy unit.
It is another main object of the invention to provide a filter cartridge of the character described, including an end cap sealing ring adhesively bonded to each end face of the cartridge to prevent radial flow between adjacent cartridges.